PIK3CA and gastric cancer: The phosphoinositide 3-kinase (PI3K) pathway plays a key role in the proliferation and survival of various cancer cells including GC.135–137 The PI3K/AKT/mTOR signaling pathway promotes tumor progression in GC through several mechanisms, including the inhibition of apoptosis, induction of drug resistance, metastasis, and angiogenesis138 (Fig. 2).